7th Grade Science Vocabulary - Cells

process in which a cell uses energy to transport a substance into or out of the cell

amino acid

building block of protein

asexual reproduction

reproduction requiring only one parent

ATP

substance in which cells store energy

autotroph

organism that can produce its own food, primarily through photosynthesis

carbohydrate

energy-rich substance found in foods such as vegetables, cereal grains, and breads; sugars and starches

cell

basic unit of structure and function in living things

cell division

process in which one cell divides into two cells, each of which is identical to the original cell

cell membrane

thin, flexible envelope that surrounds a cell and allows passage of materials into and out of the cell

cell theory

theory that all living things are made of cells, that all cells come from other cells, and that the cell is the basic unit of structure and function in living things

cell wall

: outermost boundary of plant cells that is made of cellulose

chloroplast

cell organelle containing chlorophyll that is involved in the process of photosynthesis

chromatin

threadlike coils of chromosomes

chromosome

rod-shaped cell structure that directs the activities of a cell and passes on the traits of a cell to new cells

compound

two or more elements chemically combined

cytoplasm

region between the cell membrane and the nucleus

diffusion

process by which substances move from a higher concentration of that substance to a lower concentration of that substance; primary method by which substances enter and leave the cell through the cell membrane

digestion

process by which food is broken down into simpler substances

division of labor

division of work among the different parts of an organism's body that keeps an organism alive

DNA

nucleic acid that stores the information needed to build proteins and carries genetic information about an organism

element

pure substances that cannot be separated into simpler substances by ordinary chemical processes

endoplasmic reticulum

tubular passageways in the cell through which substances such as proteins are transported

enzyme

chemical substance that helps control chemical reactions

excretion

process of getting rid of waste materials

fat

substance that supplies the body with energy and also helps support and cushion the vital organs in the body

fermentation

energy-releasing process that does not require oxygen; less efficient than respiration

heterotroph

organism that cannot make its own food

homeostasis

ability of an organism to keep conditions inside its body the same, even though conditions in its external environment change

ingestion

taking in food; eating

life span

maximum length of time an organism can be expected to live

lysosome

small; round structure , in a cell involved in the digestive activities of the cell

metabolism

sum total of all chemical activities in an organism

mitochondria

power- houses of the cell in which cellular respiration occurs

mitosis

process in which the nucleus of a cell divides into two nuclei and the formation of two new daughter cells begins

nucleic acid

large, organic compound that stores information that helps the body make the proteins it needs; DNA or RNA

nucleus

cell structure that directs all the activities of the cell

organ

group of different tissues working together; the third level of organization in an organism

organ system

group of organs that work together to perform a specific function for the organism, the fourth level of organization in an organism

organelle

"tiny organs" that make up a cell

organic compound

compound found in living things that contains the element carbon

osmosis

term given for the diffusion of water through a membrane

photosynthesis

process by which organisms use energy from sunlight to make their own food

protein

substance used to build and repair cells; made up of amino acids

respiration

process in which simple food substances such as glucose are broken down and the energy they contain is released

response

some action or movement of an organism brought on by a stimulus

ribosome

protein-making site of the cell

RNA

nucleic acid that "reads" the genetic information carried by DNA and guides the protein-making process

selectively permeable

membrane that allows certain materials to pass through, but restricts other materials from passing through

sexual reproduction

reproduction usually involving two parents in which a sex cell from each parent unite to form offspring

spontaneous generation

hypothesis that states that life can spring from nonliving matter

stimulus

signal to which an organism reacts; change in the environment

stomata

openings in the lower surface of the epidermis in a green plant that allows gases to enter and leave the plant's cells

tissue

group of similar cells that perform a special function in an organism; the second level of organization in an organism

vacuole

large, round sac in the cytoplasm of a cell that stores water, food, enzymes, and other materials